A neural impingement occurs when tissue near a nerve grows or swells into contact with the nerve. Many times, impinging tissue may pinch or compress the nerve against other structures within the body and reduce the nerve's ability to function properly. Neural impingements may often be caused by tumors, bone spurs, or soft tissue inflammation.
An impingement proximate the spinal column, e.g., a foraminal stenosis, may compress vital nerve roots as they exit the spinal column. For example, with a neural foraminal stenosis, the natural passageways (i.e., foramen) where the peripheral nerve roots exit the spine may become overgrown or otherwise restricted, and may compress/irritate the peripheral nerve root. Such irritation may result in pain and/or a loss of motor function in a limb innervated by that peripheral nerve. Other impingements may occur away from the spine. For example, in Carpal Tunnel Syndrome, the median nerve may be compressed as it passes through the carpal tunnel portion of the wrist. Other peripheral nerve compressions may include ulnar nerve compression at the elbow, nerve compression within the brachial plexus, pyriformis syndrome, or compression of any other peripheral motor nerve.
One manner of treating, for example, a spinal stenosis involves widening the foramen through surgical techniques. These procedures, such as a foraminotomy or a laminectomy, involve mechanically removing soft tissue or bone that may be impinging the neural tissue. This mechanical tissue removal may generally involve filing, cutting, and/or grinding procedures. By removing the overgrown tissue/bone, the nerve may decompress and ideally return to its normal function. Other procedures that may be used to decompress an impinged nerve may include: a discectomy (removal of all or a portion of a vertebral disc); removal of bone or disc fragments that may be compressing the nerve; removal of all or a portion of a tumor; removal of pus, fluid, or other material attributable to an infection; or removal of any other space occupying lesion or structure that may compress the nerve. Additionally, other indirect surgical procedures may be performed to decompress an impinged nerve. These may include, for example, a reduction of a spondylolysthesis; an interbody height restoration, e.g., through the insertion of a mechanical interbody spacer or bone graft; a reduction of a fracture; or an insertion of a device into interspinous space or into the facet joint space. Similar decompression techniques may likewise be performed to remove impingements against peripheral nerves.
Depending on the duration and degree of the compression, the nerve may either return to normal function following the decompression procedure or may have some degree of compromised function.